Fabrication of recycled dry cell electrode–derived graphene oxide/TiO2/polyaniline composites and assessment of their photocatalytic and electrochemical performance

Abstract

The widespread use of synthetic dyes in textiles, paper, paints, and plastics causes severe water pollution by blocking sunlight, reducing photosynthesis, and harming ecosystems and human health. To mitigate this, graphene oxide (GO) was synthesized from waste dry cell electrodes, followed by the preparation of GO-incorporated titanium dioxide/polyaniline (GO/TiO₂/PANI) composites. The composites were then characterized for their structural and elemental properties using SEM, EDX, XRD and FTIR. The photocatalytic degradation of congo red dye was systematically examined under varying dye concentrations, pH levels, contact times, and catalyst dosages. At an initial concentration of 8 ppm, 92.7% degradation was achieved within 300 minutes under visible light irradiation at neutral pH. Catalyst dosage significantly influenced performance, with concentrations of 3, 5, 7, and 10 mg per 100 mL of an 8 ppm dye solution yielding degradation efficiencies of 80–85%, 92–95%, 96–98%, and 97–99%, respectively. Furthermore, electrochemical analysis demonstrated markedly enhanced performance, with the ternary composites exhibiting a specific capacitance of 17.50–43.87 F g⁻¹—substantially higher than that of individual GO, PANI, and PANI/TiO₂ systems. These findings demonstrate that the synthesized composite possesses enhanced photocatalytic activity, achieving efficient degradation of congo red dye under sunlight at neutral pH. The improved electrochemical performance obtained through GO incorporation further underscores the potential of recycled GO in developing electrode materials for supercapacitor applications. Moreover, the recycling of waste graphite into functional GO-based materials underscores the dual benefit of effective waste reduction and value-added material regeneration, paving the way for future research in environmental remediation and energy storage.